• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.489-495
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• 2000

The 185 ribosomal RNA gene (185 rDNA) of the marine alga Porphyra sp. 723 (Bangiales, Rhodophyta) was amplified using the polymerase chain reaction and its sequence was analysed. The Porphyra species was a summer strain collected on rocks in upper intertidal zone at Ikidae, Pusan on 23rd July 1999. The fronds were $1{\~}5 cm$ long, monostromatic, and orbicular or ovate shaped, They had spinulate processes at margin of the frond, Comparison of this 185 rDNA sequence with the other Forphyra species indicates that Porphyra sp. 723 has the same 185 rDNA sequence derived from Porphyra suborbiculata (NCBI access number; AB 013180) except one base pair substitution in 2327 base pairs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.1
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• pp.35-38
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• 2003

Nuclear 18S ribosomal RNA gene (185 rDNA) from the aquaculturable seaweed Porphya tenera (Bangiales, Rhodophyta) was amplified using the polymerase chain reaction and its sequence was analysed. Complete 185 rDNA has an 1,822 bp exon and a 510 bp intron. The G+C contents of exon and intron were $48.68\%\;and\;54,90\%,$ respectively. The exon sequence showed $99.6\%$ homology to the GebBank accession number AB029880 of the Japanese P. tenera. The intron region that is inserted upstream between 568 and 1,079 showed $43.6\%$ homology to the AB029880.

• ALGAE
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• v.23 no.3
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• pp.209-217
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• 2008

Two different molecular markers, the plastid rbcL and mitochondrial cox1 genes, were used to define the taxonomic position of the northwest Pacific Ocean species currently named Gracilaria chorda. We analyzed both genes (1,222 bp for rbcL and 1,245 bp for cox1) from 18 specimens collected in Korea, Japan, and China. Phylogenetic reconstruction revealed that this organism should be classified in the genus Gracilariopsis, rather than in the Gracilaria. Thus, Gracilariopsis chorda (Holmes) Ohmi is the legitimate name for Gracilaria chorda Holmes. Within the species, the sequences differed by 8 bp (0.7%) in rbcL and 5 bp (0.4%) in cox1. Six haplotypes of cox1 tended to be geographically organized. Gp. chorda is characterized by coarse, elongate terete axes, short filiform branchlets usually at irregular intervals, an abrupt transition in cell size from medulla to cortex, cystocarps without tubular nutritive cells connecting the gonimoblast to the upper pericarp, and relatively large gonimoblast cells of the cystocarp in the specimens collected from Wando in southern Korea.

• ALGAE
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• v.35 no.2
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• pp.157-165
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• 2020

Culture isolates of the genus Hypoglossum (Delesseriaceae, Rhodophyta) were obtained and their development and morphological structure over many years were followed in the laboratory. Molecular data (rbcL, large subunit ribosomal DNA, and cytochrome c oxidase subunit I) were obtained from these strains and evidence presented to recognize the new species: Hypoglossum sabahense from Sabah, Malaysia. Because various aspects of morphology in culture specimens differ significantly from types based on field specimens we have to rely mainly on the molecular criteria in ascribing a new taxonomic name here. This also is complicated by the major lack of molecular phylogenetic evidence for Hypoglossum and other Delesseriaceae. The 'Germling Emergence Method' and 'serendipity' are proving valuable in discovering significant new taxa from laboratory cultures which otherwise might never be known.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1217-1224
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• 2018

Seaweeds produce antioxidants to counteract environmental stresses, and these antioxidant genes are regarded as important defense strategies for marine algae. In this study, the expression of Pyropia yezoensis (Bangiales, Rhodophyta) ascorbate peroxidase (PyAPX) and manganese-superoxide dismutase (PyMnSOD) was examined by qRT-PCR in P. yezoensis blades under abiotic stress conditions. Furthermore, the functional relevance of these genes was explored by overexpressing them in Chlamydomonas. A comparison of the different expression levels of PyAPX and PyMnSOD after exposure to each stress revealed that both genes were induced by high salt and UVB exposure, being increased approximately 3-fold after 12 h. The expression of the PyAPX and PyMnSOD genes also increased following exposure to $H_2O_2$. When these two genes were overexpressed in Chlamydomonas, the cells had a higher growth rate than control cells under conditions of hydrogen peroxide-induced oxidative stress, increased salinity, and UV exposure. These data suggest that Chlamydomonas is a suitable model for studying the function of stress genes, and that PyAPX and PyMnSOD genes are involved in the adaptation and defense against stresses that alter metabolism.

• Fisheries and Aquatic Sciences
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• v.21 no.8
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• pp.28.1-28.12
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• 2018

Intertidal macroalgae are exposed to many abiotic stress factors, and they must regularly react to changes in their environment. We used RNA-seq to describe how Porphyra umbilicalis (Rhodophyta) changes gene expression patterns to interact with different habitats. Tissue samples were taken from a typical habitat along the open-coast of the Northwest Atlantic, as well as from a rare, atypical habitat in an estuarine tidal rapid environment. Differential gene expression analyses suggest that pathogic bacteria and viruses may be a significant factor influencing the transcriptome in the human-impacted estuarine environment, but the atypical habitat does not necessarily induce more stress in Porphyra umbilicalis growing there. We found genes related to nitrogen transport are over-expressed in tissue from the open-coastal site compared to those from the estuarine site, where environmental N levels approach hypertrophic levels. Low N levels impede growth, but high levels are toxic to cells, and we use qPCR to show this species regulates expression of a putative high-affinity $NH_4{^+}$ transporter under low and high N conditions. Differences in expression of this transporter in these habitats appear to be inherited from parent to offspring and have general implications for adaptation to habitat in other species that are capable of asexual reproduction, as well as more specific implications for this species' use in aquaculture.

• Journal of Plant Biology
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• v.39 no.1
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• pp.23-29
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• 1996

Morphology and reproduction of Polysiphonia atlantica Kapraun et J. Norris were studied on the basis of field and laboratory cultured materials collected from the coast of Korea. The plants consisted of prostrate and erect axes with an extremely soft flaccid texture. Axes were ecorticated and had four pericentral cells. The plants except for female gametophytes had few trichoblasts. Branches in the upper portion of the thallus grew to the same level, resulting in a flat-top form. Tetrasporangia were arranged in straight series. Spermatangial branches replaced whole trichoblasts and had a 1-2 celled serile tip. The procarp had a four celled carpogonial branch. After fertilization, the carpogonium contancted the surface of the supporting cell. The formation of the auxiliary cell from the supporting cell was somewhat delayed P. atlantica from Korea was similar to P. subtilissima Montagne in some features. However, the taxonomic differences between the two species were identified in the development of branches and the number of sterile cells at the tip of spermatangial branches.

• Journal of Plant Biology
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• v.28 no.1
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• pp.45-55
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• 1985

Observations on reproduction of Rhodochorton purpureum (Lightfoot) Rosenvinge (Acrochaetiaceae, Rhodophyta) was carried out with plants from Hokkaido, Japan. This species produces no monosporangia both in nature and culture, even though it does tetrasporangia commonly. The plants from Nemuro produce neither sporangia nor gametangia, and thus vegetative reproduction is the only known way to propagate themselves. It is suggested that the vegetative reproduction occurs in nature by fragmentation of vegetative filaments after development of a rhizoid. Several different modes of rhizoid production are described. The plants from Akkeshi and Oshoro (I) produce tetrasporangia that develop into plants producing only tetrasporangia. The plants from Muroran and Oshoro (II) produce tetrasporangia that develop into gametophytes. Gametophytes of R. purpureum from Muroran produce tetrasporangia as well as spermatangia or carpogonia. Such tetrasporangia on gametophytes are presumed to be mitotic.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.633-638
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• 2002

Nuclear 18S ribosomal RNA gene (185 rDNA) from the aquaculturable seaweed Porphya yezoensis (Bangiales, Rhodophyta) was amplified using the polymerase chain reaction and its sequence was analysed. Complete 185 rDNA has an 1823 bp exon and a 514 bp intron. The G+ C contents of exon and intron were $48\%$ and $51.4\%$, respectively. The exon sequence showed $99.5\%$ homology to the GenBank accession number AB013177 of the Japanese p. yezoensis. The intron region that was inserted upstream between 568 and 1083 showed $93.4\%$ homology to the AB013177.

• ALGAE
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• v.32 no.1
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• pp.29-39
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• 2017

Geographic distributions of pathogens are affected by dynamic processes involving host susceptibility, availability and abundance. An oomycete, Pythium porphyrae, is the causative agent of red rot disease, which plagues Pyropia farms in Korea and Japan almost every year and causes serious economic damage. We isolated an oomycete pathogen infecting Pyropia plicata from a natural population in Wellington, New Zealand. The pathogen was identified as Pythium porphyrae using cytochrome oxidase subunit 1 and internal transcribed spacer of the rDNA cistron molecular markers. Susceptibility test showed that this Pythium from New Zealand was able to infect several different species and genera of Bangiales including Pyropia but is not able to infect their sporophytic (conchocelis) phases. The sequences of the isolated New Zealand strain were also identical to Pythium chondricola from Korea and the type strain from the Netherlands. Genetic species delimitation analyses found no support for separating P. porphyrae from P. chondricola, nor do we find morphological characters to distinguish them. We propose that Pythium chondricola be placed in synonymy with P. porphyrae. It appears that the pathogen of Pyropia, both in aquaculture in the northern hemisphere and in natural populations in the southern hemisphere is one species.